An epidemiologic, cytogenetic and pathologic study of spontaneous abortions is being carried out. The purpose of this study is to identify factors asssociated with spontaneous abortion and elucidate the mechanism for this association by examining associations with the karyotypic and morphologic characteristics of the conceptus. A surveillance system based on spontaneous abortions has been set up. We will test the feasibility of using this system to monitor the environment for mutagens and teratogens.